Well packer anchor

ABSTRACT

A retrievable well-packer apparatus including a body member having upper and lower expander means slidably mounted thereon for movement toward and away from each other, slip means between said expander members and slidably coupled to said body member and one of said expander means, and packing means for sealing off a well bore in response to movement of said body member relative to slip and expander means in one longitudinal direction, said packing means including elastomeric packing elements and pressure responsive parts subject to fluid pressure acting in the opposite longitudinal direction for exerting compressive force on said packing elements.

United States Patent 2,906,344 9/1959 Clark Primary Examiner-David H.Brown Attorneys-Emest R. Archambeau, .llr., David L. Moseley,

Edward M. Roney and William R. Sherman ABSTRACT: A retrievablewell-packer apparatus including a body member having upper and lowerexpander means slidably mounted thereon for movement toward and awayfrom each other, slip means between said expander members and slidablycoupled to said body member and one of said expander means, and packingmeans for sealing off a well bore in response to movement of said bodymember relative to slip and expander means in one longitudinaldirection, said packing means including elastomeric packing elements andpressure responsive parts subject to fluid pressure acting in theopposite longitudinal direction for exerting compressive force on saidpacking elements.

PATENTED SEP 7 Ian 3,603,392

sum 1 or 4 Howard L. Mc Gill INVENTOR s4 j B fl g (W ATTORNEYPATENTEUSEP mu 3,603,392

SHEEI 2 OF 4 r- *1 1 77 N I I l 1 Howard L. Mc Gill INVENTOR A TTORNE YPATENTEDSEP 71971 SHEET 3 [IF 4 FIG. 5A

WELL PACKER ANCHOR This is a division of application Ser. No. 722,912,filed Apr. 22, 1968.

This invention relates generally to retrievable well packers used inwell bores, and more specifically, to a new and improved retrievablewell packer which can be run and set in casing on a pipe string andwhich will hold high pressure from above or below.

In conducting pressure operations such as fracturing, acidizing, squeezecementing and testing in a well bore, well tools commonly called packersare run into the well bore on tubing or drill pipe and set at a selectedpoint in order to isolate the zone to be pressurized. After theoperation is completed, the packer can be retrieved to the surface.Particularly where such pressure operations are conducted at relativelyshallow depths in a well, any above 3000 to 4000 feet, it is goodpractice to use what is commonly called a tension set packer becausethere may not be sufficient pipe weight available to set a compressionset packer and maintain it set against high pressure from below. Intension packers, the slips and packing are generally arranged to be setby upward strain or tension in the pipe string so that high pressurebelow the packer reinforces the setting, instead of opposing it as isthe case of a compression set packer.

However, conditions may arise when using a retrievable tension packerwhen the high pressure is in favor of the annulus above the tool. Thismay occur, for example, during swab-testing of a cement job or the likewhere the static head of fluids below the packer is substantiallyreduced. In such event, the downward force on the tool due to highpressure from above adds to the strain or tension already being appliedto the pipe string to set the packer so that the risk arises ofoverstraining and possibly pulling the pipe string in two. This is, ofcourse, undesireable and cannot be effectively prevented by reducing thetension in the pipe string because the packer, being tension set, maybecome unseated or may slide downwardly in the casing to an improperlocation.

The present invention provides a new and improved retrievable wellpacker which is settable in tension to isolate a well zone to bepressurized, and which is provided with various features to obviate theaforementioned problems. The packer remains sealed off and set whetherthe higher pressure is acting from below or above.

SUMMARY OF THE INVENTION Generally speaking, a retrievable well packerin accordance with the concepts of the present invention comprises abody member adapted for connection to a pipe string and carrying upperand lower expander and drag means which are mounted for limitedlongitudinal movement on the body member. Normally retracted slip meansare also mounted on the body member between the expander means and canbe shifted into anchoring engagement with a well conduit by movement ofthe expander means relatively toward each other. The slip means can havea sliding connection to one of the expander means as well as to the bodymember, and are supported in anchoring engagement with the wall conduitby both expander means acting simultaneously.

The well packer further includes a packing assembly including packingelements which are sealed against the well conduit in response to forceapplied to the body member in one longitudinal, direction, movement insaid one direction being prevented,,however, by the slip means. Inresponse to fluid pressure acting in the opposite longitudinaldirection, the packing assembly and the body member are shiftable to alimited extent along the well conduit in said opposite direction whilethe packing elements remain sealed against the well conduit, whereuponcoengageable means coacting between the body member and said expanderand slip means function to cause the slip means to prevent furthershifting in said opposite direction. Thus the well packer of the presentinvention will hold pressure acting in either longitudinal direction,and

LII

the shifting mentioned is quite limited in order to protect the pipestring from undue strain. When desired, the slip means and the packingelements can be retracted so that the packer can be moved to anothersetting point or removed from the well bore.

The novel features of the present invention are particularly set forthin the appended claims. One preferred embodiment of the presentinvention is illustrated in the accompanying drawings in which:

FIGS. IA and 1B are longitudinal sectional views, with portions in sideelevation, of a well packer in accordance with this invention, FIG. 18forming a lower continuation of FIG. 1A;

FIG. 2 is a cross section on line 2-2 of FIG. 1A;

FIG. 3 is a cross section on line 3-3 of FIG. 1A;

FIG. 4 is a schematic plan view of a slot configuration which is used toenable selective control over relative movement between parts;

FIGS. 5A and 5B are views similar to FIGS. 1A and 1B except with thepacker set in a well conduit;

FIGS. 6A and 6B are similar views showing the relationship of packerparts when a sufficiently high pressure exists in the well annulus abovethe packer; and

FIG. 7 is a longitudinal sectional view with portions in side elevation,of a modified structure in accordance with the present invention.

Referring initially to FIGS. 1A and 1B, an apparatus which incorporatesthe principles of the present invention includes a tubular body memberor mandrel 12 having a central passage 13 through which fluid can flow.Threaded collars l4 and 15 can be provided at the upper and lower endsof the mandrel 12, the upper collar 14 being coupled to a running-instring of tubing or drill pipe 16 which extends to the earths surface.The mandrel 12 carries an anchoring structure 18 which includes atubular cage 19 and drag elements 20, the cage 19 being secured to atubular sleeve 21 which is coupled by a swivel connection 22 to an upperexpander member 23. One or more lug elements 24 extend outwardly fromthe mandrel l2 and engage within a slot system 25 formed on the interiorof the sleeve 21, the lugs and slot system cooperating to providecontrol over relative longitudinal movement between the mandrel and theanchoring structure as will be more fully described.

Circumferentially spaced slip elements 27 are slidably coupled to theexpander member 23 and are mounted on the mandrel 12 for bothlongitudinal and lateral movement relative to the mandrel. The slipelements 27 have peripheral wickers or teeth 28 which can bite into andgrip the well casing in order to prevent movement in either direction ina well casing.

A lower tubular cage 29 carries drag elements 30 and is secured to alower expander member 31. The cage and expander member 29 and 31 areslidable upwardly relative to the mandrel 12 to a position whererespective shoulders 32 and 33 on the cage and the mandrel engage tolimit relative movement. A bore 34 in the cage and expander member is,however, sized to permit unlimited upward relative movement of themandrel 12 within the cage and expander member.

A packing structure 36 is slidably carried by the mandrel l2 andincludes an inner sleeve 37 having a lower abutment 38, and an outersleeve 39 having an upper abutment 40. The respective sleeves 37 and 39are slidable along each other and can have a spline connection 41 toprevent relative rotation. One or more conventional elastomeric packingrings 42 are mounted around the inner sleeve 37 between the upperandlower abutments 40 and 38, the rings: being expandable into sealingengagement with a well casing wall by movement of the abutments 40 and38 relatively toward each other. The outer sleeve 39 has an inwardlyextending annular piston section 44 which is sealed against an outerperipheral surface of the mandrel 12 by an O-ring seal 45 or the like.Moreover, an O-ring seal 46 prevents fluid leakage between the inner andouter sleeves 37 and 39, whereby a variable volume chamber 47 is formedbetween the outer sleeve 39 and the mandrel 12. This chamber 47 iscommunicated with the well annulus below the packing rings 42 by asuitable passage which can conveniently be formed by an annular space 48between the mandrel 12 and the inner sleeve 37. Consequently, fluidpressure below the packing rings 42 can act on the lower face 49 of thepiston section 44, while fluid pressure above the packing rings can acton the upper face 50 of the piston section. With this arrangement, oncethe packing rings 42 are ex panded into sealing engagement with a wellcasing wall, high pressure in the well annulus above the packing ringscan act on the piston section 44 to impose compressive force on thepacking rings for purposes which will become more apparent hereafter.Upward movement of the packing assembly 36 along the mandrel 12 islimited by engagement of the piston section 44 with the lower cage 29,and upwardmovement of the mandrel 12 within the packing assembly islimited by a transverse surface 51, which may be conveniently providedby the collar 15.

Turning now to a more detailed consideration of various other structuralfeatures of the present invention, the upper tubular cage 19 has aplurality of circumferentially spaced, radially directed recesses 54which receive drag blocks 20. The drag blocks can be urged outwardly bycoil springs 55 or the like into frictional engagement with a wellcasing, and outward movement of the blocks can be limited by bands 56, Asea] barrier 57 prevents debris in the well bore from getting in betweenthe cage and the mandrel. The swivel connection 22 can be suitablyformed by flanged sleeves 58 and 59 which are threadedly secured to theextension sleeve 21 and the upper expander member 23, respectively. Thesleeves 58 and 59 have coengaging annular portions 60 and 61 to providea rotational coupling.

The slip elements 27 are mounted on a ring member 63 which is relativelyslidable on the mandrel 12 below an annular stop shoulder 64. The ringmember 63 can be an integral piece as shown in cross section in FIG. 2,or can be formed in segments secured together by threaded studs. In anyevent, the ring member 63 has circumferentially spaced, axially diaposedrecesses 65, each of which receives acentral portion 66 of a respectiveslip element 27 to provide a lateral guide therefor. As previouslynoted, the ring member 63 can slide downwardly relative to the mandrel12, however upward movement is limited by the downwardly facing stopshoulder 64 on the mandrel.

The slip elements 27 have upper inner-inclined surfaces 67 cooperablewith the outer inclined surfaces 68 on the expander member 23 wherebylongitudinal movement of the elements relative to the expander memberwill cause lateral shifting thereof. A dove-tail flange and grooveconnection 69 slidably couples each slip element 27 to the upperexpander member 23 so that the slip elements are retracted by upwardmovement of the expander member 23 relative o the slip elements.

The lower drag cage 29 has recesses 71 receiving drag blocks which areurged outwardly by coil springs 72. Outer inclined surfaces 73 on theexpander member 31 are engageable with inner inclined surfaces 74 on theslip elements 27 for wedging the elements outwardly. However, there isno sliding connection between the lower expander member 31 and the slipelements 27.

The slot system 25 which cooperates with the mandrel lugs 24 may best beunderstood by considering FIGS. 3 and 4. As shown in FIG. 3, there canbe three lugs 24 circumferentially spaced about the mandrel 12, each ofwhich engages in a slot configuration formed interiorly of the sleeveextension 21 and shown somewhat schematically in FIG. 4. Each slotconfiguration is longitudinally stepped and includes-lower and uppertransverse channels 77 and 78 connected by a short vertical channel 79.An elongated vertical channel 80 connects with upper transverse channel78. In the running-in condition of parts shown in FIGS. 1A and 1B, thelugs 24 are positioned in the lower transverse channels 77 to preventrelative movement of the upper expander member 23 along the mandrel 12.However, it will be appreciated that by applying right-hand torque tothe mandrel 12 while lifting the mandrel upwardly, the lugs 24 can bemoved into the elongated vertical channels to permit a substantialamount of relative movement between the upper expander member 23 and themandrel. Moreover, the transverse form of the upper channels 78 providestransverse surfaces or shoulders 81 which can be engaged by the lugs 24in response to downward movement of the mandrel 12, whereby downwardforce on the mandrel can be applied to the upper expander member 23 forreasons which will be subsequently pointed out. Of course, it will beunderstood that more or less than three lugs 24 can be on the mandrel12, in which case the slot system 25 will include a like number of slotconfigurations in which the lugs engage.

In operation of the structure thus far described, it will be apparentthat the assembled tool can be connected to the lower end of the pipestring 16 and pushed downwardly along the well casing to setting depthas additional joints of the pipe string are added in end-to-endrelation. The lower drag blocks 30 slide along the well casing wall, andthe coengaged shoulders 32 and 33 on the mandrel and lower cage maintainthe lower expander member 31 in spaced relation to the slip elements 27.The upper drag blocks 20 are also sliding along the casing wall as thedownward motion of the mandrel 12 is being transmitted to the anchorassembly 18 by engagement of the lugs 24 with the lower transversechannels 77. The slip elements 27 are being held in retracted positionsby their sliding connections 69 with the upper expander member 23,together with engagement of the mounting ring 63 underneath the mandrelshoulder 64. Of course, the packing rings 42 are in their inherentlyretracted positions so that well fluids can pass between the rings andthe well casing wall.

When it is desired to set the packer, right-hand torque coupled with anupward strain on the pipe string 16 will position the lugs 24 within theelongated vertical channels 80 as previously described, the drag blocks20 functioning to prevent movement of the upper cage member 19 and theupper expander member 23. As the mandrel 12 is pulled upwardly, thelower mandrel shoulder 51 engages the lower end of the inner sleeve 37to elevate the packing assembly 36 as well as the lower drag assembly 29and the lower expander member 31 toward the slip elements 27 until theirteeth 28 bite into and grip the well casing wall. Then the lowerexpander member 31 and the outer sleeve 39 of the packing assembly 36cannot move any further upwardly, whereby continued upward movement ofthe mandrel 12 telescopes the inner sleeve 37 within the outer sleeve 39and effects compression and lateral expansion of the packing rings 42until their outer peripheries seal against the well casing wall. Apredetermined amount of upwardly strain is maintained in the pipe string16 at the earths surface in order to maintain the tool in set conditionas shown in FIGS. 5A and 53.

It should be specifically noted at this point that both of the expandermembers 23 and 31 are engaging the slip elements 27. This engagedrelationship will be maintained during the operation of the packer anduntil it is desired to release the tool for retrieval from the well.With the slip elements 27 set and the packing 42 expanded, the well borebelow the tool can be pressurized as desired and the slip elements willprevent upward movement while the packing rings seal off the wellannulus.

Should a sufficiently high pressure exist in the annulus above thepacker, various of the tool parts can shift to the positions shown inFIGS. 6A and 68 where the slip elements 27 remain anchored againstmovement and the packing rings 42 remain expanded. This shifting actionresults due to the high pressure acting downwardly on the expandedpacking rings 42 with the resulting force being transmitted to the pipestring 16 through the lower shoulder 51, tending to stretch the pipestring. A limited amount of such stretching can occur and is accompaniedby downward movement of the mandrel 12, thereby moving the lugs 24downwardly within the vertical channels 80 until the lugs bottom againstthe shoulder surfaces 81 at the lower end of the channels.

During this movement, the packing rings 42 merely slide downwardly alongthe casing in expanded condition and remain sealed against the wellcasing wall. This will occur because the lower fluid pressures areacting on the lower face 49 of the piston section 44 while the highpressures are acting on the upper face 50, the pressure differentialacting on the area A as downward force which is applied to the upper endof the packing rings 42 by the upper abutment 40. lt will be rememberedthat upward strain is still being exerted on the pipe string 16 so thatcompressive force is being applied to the lower end of the packing rings42 by the lower abutment 33.

7 Accordingly, since compressive force is being exerted on both ends ofthe packing rings, the rings will not retract but can slide downwardlyalong the casing wall in expanded and sealing condition. However, whenthe lugs 24 engage the shoulder surfaces 81, further downward shiftingis not possible and the load on the tool due to high pressure from aboveis transmitted through the lugs 24 and shoulder surfaces 81 to the upperexpander member 23 which is supported by the slip elements 27 and cannotmove downwardly. Thus the casing itself supports the load and there isno danger of damaging the pipe string by overstretching it. The actualextent of downward shifting of the mandrel 12 and packing assembly 36 isactually quite short compared to prior art devices of this general type,and may be only two or three inches. This feature provides a significantadvantage over such prior tools, particularly when the packer is set atshallow depths and the length of the pipe string is consequently short.

If the pressure in the annulus is reduced, tension is still being heldin the pipe string 16 and the string can contract and shift the packingassembly 36 and the mandrel 12 back upwardly to their original positionwith the upper and lower expander members 23 and 31 cooperating with theslip elements 27 to prevent further upward movement. In fact, as long astension is held on the pipe string, the packing assembly 36 and themandrel 12 can shift to and fro and it will be appreciated that the wellbore remains sealed off to prevent any fluid movement past the tool. Theslip elements 27 remain anchored against the well casing wall and remainsupported in anchoring condition by both the upper and lower expandermembers 23 and 31.

To unset the tool, pressures above and below the packer are equalized byoperation of a suitable bypass valve (not shown) as upward strain on thepipe string 16 is relieved and as the mandrel 12 is moved downwardly bylowering the the pipe string. This relieves the compressive force on thepacking assembly 36 and the packing rings 42 will inherently retract.The mandrel shoulder 32 will engage the cage shoulder 33 to push thelower expander member 31 out from behind the slip elements 27. The lugs24 are manipulated back into the lower transverse channels 77 of theslot system 25 to lock the upper expander member 23 and the dragassembly 19 in their upper positions on the mandrel 12. Then an upwardpull on the pipe string 16 will lift the upper expander member 23 andcause the slip elements 27 to shift inwardly along the inclined surfaces68 of the expander member 23 to their retracted positions, whereupon thetool is free to be moved upwardly or downwardly within the casing.

If a tubing tester valve is utilized which is opened and closed bymovement of the pipe string 16, it will be appreciated that the slipelements 27 can be set against the casing by merely manipulating thepipe string as previously described in order to position the lugs 24within the vertical channels 80 of the slot system 25. Then the pipestring 16 can be lowered to engage the lugs 24 with the shouldersurfaces 81, whereupon the slip elements 27 can be shifted outwardlyinto gripping contact with the casing by movement of the upper expandermember 23 toward the lower expander member 31. With the slip elements 27set and the lugs 24 engaging the shoulder surfaces 81, a false bottom isprovided for the lower end of the pipe string 16 to enable operation ofa tubing tester valve or a circulating valve or the like.

It is sometimes desirable to be able to safety the tool during removalof same from the well. In other words, some operators may desire tocompletely disarm the tool immediately before retrieving it so that itis impossible to again set the slips and the packing in the well bore. Astructure for accomplishing this end is also shown in FIG. 1A. Aninwardly biased latch lug 84 is received in a radial bore 85 in the wallof the cage extension sleeve 21. The latch lug 84 is normally retainedoutwardly and in inoperative position by a retaining sleeve 86 which isthreaded at 87 to the expander member 23 and slidably and corotativelycoupled to the flanged sleeve 58 on the cage extension sleeve 21. Byrotation of the extension sleeve 21 relative to the expander member 23,the retainer sleeve 86 can be fed upwardly by the threads 87 to aposition clear of the latch lug 84, whereupon the lug can springinwardly against the mandrel 12 and into a detent groove or recess 88formed above a shoulder 89 on the mandrel. When this occurs, it isimpossible to again manipulate the mandrel lugs 24 within the slotsystem 25 in a manner to enable setting the slips and packing.

To operate the disarming mechanism, the mandrel 12 is first manipulatedto place the mandrel lugs 24 in the long vertical channels 80, and thenthe pipe string 16 is moved downwardly to set the slip elements 27against the casing wall. With a small amount of pipe weight beingapplied, the slip elements cannot be rotated within the casing, and theupper expander member 23 cannot rotate due to the dove-tail" connection69 between the slip elements and the expander member. Accordingly,sufficient torque can be applied to the pipe string 16 to rotate theupper drag elements 20 within the casing and relative to the expandermember 23, such relative rotation being permitted by the swivelconnection 22. Although the upper drag elements are sufficientlyresistive to movement to enable setting and unsetting the tool aspreviously described, the elements can be forced by torque appliedthereto by the mandrel lugs 24 against the sides of the channels 80 toslide around the inner periphery of the casing. Such relative rotationcauses the retaining sleeve 86 to feed upwardly until the latch lug 84is released. Then the mandrel 12 can be lowered and manipulated to placethe lugs 24 back within the transverse channels 77, and where themandrel recess 88 is located adjacent the latch lug, allowing the lug tosnap into the recess. Now it is impossible to elevate the mandrel 12relative to the upper expander member 23 or the slip elements 27.Accordingly, the tool cannot again be seton this trip into the well andthe operator can pull the tool from the well as fast as he desireswithout the fear that the tool will, by some fortuitous circumstance,accidentally hang up and set in the casing. If desired, a lower detentgroove 90 can be provided in the mandrel 12 so that the mandrel can belocked relative to the upper expander member '23 with the lugs 24 in theupper transverse channels 78 as well.

A modified form of the packing assembly of the present invention isshown in FIG. 7. In this: embodiment, the inner sleeve 37, on which thepacking rings 42 are mounted, and the lower abutment 93 are rigidlysecured to the lower end of the mandrel 12 by threads 94. The annularpassage 95 between the sleeve 92 and the mandrel is communicated withthe well annulus by one or more ports 96. Moreover, clutch lugs 97 and98 are provided respectively on the outer sleeve 99 and the lower end ofthe cage 100, the clutch lugs being engaged by upward movement of thepacking assembly.

The structure shown in FIG. 7 operates in a similar fashion to the firstdescribed embodiment. However, if the threads 94 are formed asrelatively coarse left-hand threads, an additional safety or disarmingfeature is provided. The slip elements 27 and the packing rings 42 canbe expanded by upward strain on the pipe string 16 and then the mandrel12 can be rotated to the right. Due to the frictional engagement betweenthe lower expander member 31 and the slip elements 27, the clutchengagement between the cage 100 and the outer sleeve 99, and due furtherto the spline connection between the outer sleeve 99 and the innersleeve 92, the lower abutment 93 will be held against rotation so thatrotation of the mandrel 12 will disengage the threads 94. When thisoccurs, the mandrel 12 can be pulled upward through the packing assemblyas well as the lower expander and drag assembly, leaving these elementsin the well bore where they can be subsequently pushed to the bottom orretrieved in a conventional manner as desired.

It will be appreciated that the entire tool shown in the drawings couldbe inverted or turned upside down and then run into a well bore, inwhich case the tool could be set in compression by pipe weight ifdesired. Also, the rotational directions for setting and unsettingmovement applied to the pipe string at the surface are a function of theslot system 25, which can be arranged for right-hand or left-hand torqueas desired.

It will be apparent that the present invention provides a new andimproved retrievable well packer which is settable in tension and whichwill hold pressure in either direction. Since certain changes ormodifications may be made in the present invention without departingfrom the inventive concepts, it is the aim of the appended claims tocover all such changes and modifications falling within the true spiritand scope of the present invention.

lclaim:

1. Apparatus for use in a well bore comprising: a body member; normallyretracted slip means capable of being shifted laterally of said bodymember; expander means having a slidable spline connection to said slipmeans so that movement in one direction relative to said slip meanscauses expansion of said slip means and movement in the oppositedirection causes retraction of said slip means; annular ring meanshaving a radially slidable coupling to said slip means for mounting saidslip means for sliding movement along said body member; and stop meansincluding coengageable shoulder surfaces on said ring means and saidbody member for limiting sliding movement of said slip means along saidbody member in said opposite direction.

2. The apparatus of claim 1 wherein said radial slidable coupling isprovided by recess means in said slip means, portions of said ring meansbeing slidably received in said recess means.

3. The apparatus of claim 1 further including selectively operablecoengageable means on said body member and ex: pander means for securingsaid expander means to said body member in movement transmittingrelationship in spaced longitudinal relative positions of said bodymember and said expander means.

1. Apparatus for use in a well bore comprising: a body member; normallyretracted slip means capable of being shifted laterally of said bodymember; expander means haviNg a slidable spline connection to said slipmeans so that movement in one direction relative to said slip meanscauses expansion of said slip means and movement in the oppositedirection causes retraction of said slip means; annular ring meanshaving a radially slidable coupling to said slip means for mounting saidslip means for sliding movement along said body member; and stop meansincluding coengageable shoulder surfaces on said ring means and saidbody member for limiting sliding movement of said slip means along saidbody member in said opposite direction.
 2. The apparatus of claim 1wherein said radial slidable coupling is provided by recess means insaid slip means, portions of said ring means being slidably received insaid recess means.
 3. The apparatus of claim 1 further includingselectively operable coengageable means on said body member and expandermeans for securing said expander means to said body member in movementtransmitting relationship in spaced longitudinal relative positions ofsaid body member and said expander means.